During operation of work machines, it is sometimes desirable to move a work tool in a vibratory manner to accomplish some purpose. For example, an operator of earthworking machine having a work tool such as a bucket may desire to cause the bucket to move in a vibratory manner to shake material out of the bucket that does not readily fall out, to cause the bucket to penetrate hard material such as clay or rock, to compact a surface, or to perform some other function.
In the past, the standard method for vibrating a work tool has been for the operator to rapidly move the work tool control, such as a joystick or lever, back and forth until the task was completed. This involves rapid motion by the operator that, over time, can become tedious and tiring. This technique is also only good for certain work functions, such as shaking material out of the tool. Other functions, such as vibratory compaction of a surface, cannot be efficiently performed by manual operation.
With the advent of electro-hydraulics, it has become possible to automate control of work tools in many ways that required manual control in the past. Computer-based controllers can be programmed to operate electro-hydraulic valves and solenoids with great precision, thus alleviating many of the difficult, tedious, tiring and time-consuming tasks that operators previously had to perform.
In U.S. Pat. No. 6,725,105, Francis et al. attempt to make the manual process more efficient by introducing an abrupt mode during bucket shakeout operations. The motion of the work tool, i.e., bucket, changes from a smooth mode to an abrupt mode under certain operating criteria to make the shaking procedure more effective. However, manual manipulation is still required, and the abrupt mode still does not address other work functions, such as compacting.
In U.S. Pat. No. 5,860,231, Lee et al. discloses a system which automates the vibratory motion of a work tool by operator selection of a vibratory mode. The automatic method allows for work tool vibratory applications for several purposes, such as excavating, ground breaking, ground hardening (compaction), and the like. The operator, however, must still assert control over the work function by moving a joystick or lever to select desired amplitudes and frequencies of vibrations.
The present invention is directed to overcoming one or more of the problems as set forth above.